CM871 and CM876 Electronic Control Systems, ISX and ISM Engines – Engine Brake Does Not Operate

Engine brake on/off switch is off

Turn on the switch.

Programmable parameters or selected features are not correct

Check the programmable parameters and the selected features with an electronic service tool. Set the parameters and features again, if necessary. Refer to Procedure 019-079 in Section 19.

Electronic fault codes active or high counts of inactive fault codes

Refer to Section TF for fault code troubleshooting.

Engine brake on/off switch or circuit is malfunctioning

Check the engine brake on/off switch and circuit. Refer to Procedure 019-034 in Section 19.
Refer to Procedure 019-035 in Section 19.

Engine brake solenoid, harness or connectors are loose, broken or have an open circuit

Check the engine brake circuit, solenoid, and harness connectors. Check the engine brake harness, solenoids, and grounding for continuity. Refer to
Procedure 019-136 in Section 19.
Refer to Procedure 020-024 in Section 20. The preceding procedure refernce is in the ISM, ISMe and QSM11 Service Manual, Bulletin 3666322. The following two procedure can be found in the Signature™, ISX and QSX15 Service Manual, Bulletin 3666239.
Refer to Procedure 020-004 in Section 20.
Refer to Procedure 020-015 in Section 20.

Clutch switch or circuit is malfunctioning

Check the clutch switch adjustment, switch, and circuit. Refer to Procedure 019-009 in Section 19.
Refer to procedure 019-010 in Section 19.

Accelerator pedal or lever position sensor or circuit is malfunctioning

Check for foot pedal restriction. Check the accelerator pedal or lever position sensor and circuit. Refer to Procedure 019-085 in Section 19.

Service brake pressure switch or circuit is malfunctioning

Check the service brake pressure switch and circuit. Refer to the OEM service manual.

Engine electrical ground is malfunctioning

Check for poor battery and chassis grounds. Check ground wires or cables for loose connections. Check the following grounds, make sure they are secure, clean, and on a non-painted surface: engine block ground, chassis (or frame rail) grounds, ECM grounds, alternator and starter negative posts. Disconnect and clean battery cable connections.

Lubricating oil leak (internal)

Check the engine brake control valve and the engine brake piston. Refer to Procedure 020-024 in Section 20. The preceding procedure can be found in the ISM, ISMe and QSM11 Service Manual, Bulletin 3666322. The following procedures can be found in the Signature, ISX and QSX15 Service Manual, Bulletin 3666239.
Refer to Procedure 020-017 in Section 20.
Refer to Procedure 020-019 in Section 20.

Engine brake lubricating oil passage is restricted

Check the engine brake assembly for restriction. Refer to Procedure 020-024 in Section 20. The preceding procedure can be found in the ISM, ISMe and QSM11 Service Manual, Bulletin 3666322. The following procedure can be found in the Signature, ISX and QSX15 Service Manual, Bulletin 3666239.
Refer to Procedure 020-004 in Section 20 .

Engine brake adjustment is not correct

Adjust the engine brakes. Refer to Procedure 020-024 in Section 20. The preceding procedure can be found in the ISM, ISMe and QSM11 Service Manual, Bulletin 3666322. The following procedure can be found in the Signature, ISX and QSX15 Service Manual, Bulletin 3666239.
Refer to Procedure 020-004 in Section 20.